Manufacture of Steel Plates

Steel products are used widely; in cutlery, surgical instruments, roofs, rails, watches, weapons, aerospace. Be it tin plated steel or stainless steel, this alloy of iron and carbon is notably visible in structures of all sorts; bridges, ships, spacecraft.

Steel and its properties:

Certain properties of the alloy which help speed up the steel-making process are:-

● When pressure is gradually increased, steel is capable of resistance. The hardness of steel is one of its chief properties. 

● When steel deforms and tries to change shape, it has a low tendency to snap before fracturing. Thus, steel is tough.

● When pressure is gradually increased, it does not change its shape easily. This property is known as ‘yield strength’.

● The threshold strength of steel, the toughness beyond which steel breaks, is known as 'tensile strength' as opposed to the aforementioned yield strength.

● Steel is malleable. In other words, it can be beaten, hammered, pressed into sheets without breaking.

● Steel is ductile. Ductility refers to the process of the creation of wires and other shapes using the material.

Process of Steel-making:

Steel mills follow several steps in order to produce sheets of this alloy. Some of the procedures involve-

● Melting coke, limestone, and iron in a blast furnace.

● The impurities present in the resulting mixture is removed by the creation of primary steel by dipping the red-hot iron in an oxygen furnace.

● Coke helps turn the input (iron ore) into plain iron via combustion.

● Slag is produced when limestone and silica combine.

● Oxygen is passed through the furnace, which oxidizes silicon, phosphorus, and manganese, thus greatly reducing the amount of carbon.

● Temperatures around 1650 degrees centigrade are raised in the electric arc furnace using highly powered currents.

● Ingots of steel are soaked later at 1200-1300 degrees centigrade.

● After bringing the ingots out of the pits where soaking was carried out, slabs and billets are produced according to the requirements.

The final steps in steel-making are:

● Quenching- A form of heat treatment in which steel is cooled rapidly in order to strengthen and harden it. Steel usually has a uniform, layered pearlitic structure. This grain structure consists of ferrite and cementite. But such a structure is not desirable as it is soft. Once heated to a temperature beyond 727 degrees centigrade, followed by cooling, the crystal structure of steel is transformed into a hardened, strengthened martensite. 

● Tempering- A form of heat treatment in which steel is heated below the critical point, thus increasing its toughness. This process is carried out after quenching to get rid of the extra hardness of the material. Tempering leads to an increase in the ductility of steel.

● Annealing- A heat treatment process in which the physical and chemical properties of steel are altered to enhance its ductility, thereby reducing hardness. It is primarily a recrystallization procedure. The number of dislocations in the lattice of steel decreases, leading to changes in its toughness. Annealing is carried out to soften the alloy so that it becomes easier to reform its shape. 

Steel-making is quite an arduous process. Therefore, the next time you purchase sheets made out of steel, make sure it is of the finest quality imaginable, color coated steel, for example. Since steel happens to be the foundation of this nation’s construction as well as the economic sector, goods from JSW Coated are products of the most potent blast furnaces in this country.